meter size barrier
(one meter barrier)
(a barrier to planet formation on the order of a meter diameter)
The term meter size barrier (or one meter barrier) is used for
aspects of planet formation that would seem to
limit a planetary embryo's growth
very roughly a meter in size (e.g., the range of centimeters to a few meters).
A number of mechanisms fall within this definition, such as:
- bouncing barrier - while specks of dust might stick together when they meet, after a certain size, they seem more likely to bounce off each other.
- radial-drift barrier - the interaction of objects with a surrounding protoplanetary disk produces a tendency to migrate toward the star. The optimum size for such migration is on the order of a meter diameter, and at that size, all would seem to migrate into the star.
- fragmentation barrier - collisions between the embryos would be violent enough to break them apart.
The term meter size barrier is sometimes specifically intended to
mean these last two.
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